The invention relates to objects bearing visible images on curved image field surfaces along with an encodement that may be associated with the visible image and can be captured, decoded and reproduced as data, aural and/or visual information and methods of producing the same, and particularly to such encodements as are invisible to the human eye under normal light conditions.
It is well known to imprint data on various articles and objects, including printed media, labels, containers, vehicles, etc., in the form of a machine readable, code or xe2x80x9csymbologyxe2x80x9d that is visible to the eye but requires a reader to read and decode. The terms xe2x80x9csymbologyxe2x80x9d or xe2x80x9csymbologiesxe2x80x9d are generally employed to denote spatial patterns of symbology elements or marks, wherein each mark has a shape and separated from an adjacent mark by a spacing between the marks, whereby information is encoded in the shapes and/or the spacings between the marks, and embrace bar codes and other codes as described further below. Typically the decoded information output by the reader is used by a machine in a process of identification of the article and to associate it with other data, e.g. unit price and restocking code, which may be displayed and printed out. A great many symbologies and specialized symbology readers have been adopted over the years for encoding data. A history of one-dimensional and two-dimensional bar codes and readers that have been adopted and standardized is set forth in U.S. Pat. Nos. 5,591,956; 5,583,331; and 5,854,478, all incorporated herein by reference.
It is also known to encode aural information as such machine readable bar codes associated with images on media so that aural information or sound can be reproduced from the encoded symbology. Such systems are shown, for example, in U.S. Pat. Nos. 5,276,472 and 5,313,235 in relation to photographic prints, and in U.S. Pat. Nos. 5,059,126 and 5,314,336 in relation to other objects or printed images.
Typically such symbologies, e.g. bar codes, are intended to be printed onto a planar surface and read either by a linear scanner or a two-dimensional linear scanner or a planar imager, e.g., a CCD or CMOS array imager. However, it is also known to print visible bar codes on curved surfaces, wherein the bar codes are read by scanners. Typically, only simple, low data content, bar codes are printed on known curved surfaces to avoid using too much space on the object or media and to present the small area bar code in a more linear image field to ease reading it with a simple bar code scanner. For example, soft drink cans are imprinted with product identification bar codes that extend in parallel with the axis of the can. Such bar codes are read out by generally aligning the bar code with the linear scanner so that the line portion of the bar code that is scanned lies in a plane. In this case, it is necessary to align the bar code to the linear scanner when the bar code is scanned. In other cases, only a very short bar code is imprinted on a curved image field that has a relatively large radius of curvature, so that the image of the bar code is relatively linear to the scanner.
Additionally, a number of other approaches have been undertaken to be able to accurately read bar codes that are printed upon a container or a flexible label such that it is inherently in a curved field as described in the above-incorporated ""331 patent, for example. The curvature is typically compensated for using software for processing the scanned symbology element data and/or optical mirror systems for oscillating the scanning beam to compensate for the curvature as described therein.
The above-referenced, commonly assigned and pending patent applications disclose recording xe2x80x9cvariable dataxe2x80x9d as an invisible xe2x80x9cencodementxe2x80x9d located in an image field on media on a photographic print image or a print that is produced by other means and reproducing the encodement as aural or sound information. The term xe2x80x9cvariable dataxe2x80x9d includes data that varies from print to print and contains information related to the visible print image. The xe2x80x9cencodementxe2x80x9d is preferably formed of a two-dimensional symbology that is relatively dense and is at least co-extensive in area with the visible photographic image to maximize the amount of sound information that can be recorded. The encodement is invisible or substantially invisible to the human eye when viewed under normal viewing conditions, that is, facing the viewer and under sunlight or normal room illumination such as incandescent lighting.
The above-referenced application Ser. No. 08/931,575, incorporated herein by reference, discloses systems for recording and reading of encodements of this type. The invisible encodement image is illuminated and the illuminated image is captured by a planar imager, e.g. a CCD array imager, and decoded and played back as sound through various sound reproduction systems. During reading, in order to image the encodement and capture and decode the symbology accurately, it is necessary to locate the planar imager parallel with the image field and generally in alignment with a central point of the image field or visible print. Otherwise, part of the encodement will not be imaged by the planar imager and/or the symbology will be distorted if the image field plane is skewed to the plane of the planar imager. The above-referenced U.S. patent application Ser. Nos. 09/122,502, and 09/121,907, which are both hereby incorporated herein by reference, set forth systems and methods for assisting the user of a hand held planar imager in achieving the optimal alignment with a relatively planar image field.
In the above-described systems and methods, it is assumed that the media or surface on which the visible image and the invisible encodement are printed or otherwise formed within the image field is flat or planar. Moreover, the encodement is generally specified to constitute any of the known symbologies that have been devised or may be devised in the future that are intended to be printed upon such a planar surface, preferably such two-dimensional symbologies that are capable of high density data storage.
Not all print images and image planes are necessarily planar. It would be desirable to provide a simple and easily implemented manner implementing such encodement technology in non-planar image fields on media or surfaces of various types using a simple scanner or reader capable of reading encodements printed on both curved and flat image fields.
The invention is defined by the claims. The invention, in its broader aspects, provides objects that have or present in use non-planar media or surfaces with image fields that are curved at least in part and contain recorded encodements and visible images. In accordance with the invention, the recorded symbology constituting the encodement is modified to compensate for distortion of the symbology introduced by imaging the curved symbology portions as planar symbology image portions. The compensation or adjustment of the symbology ensures that the encoded information is accurately captured by the scanner and read, decoded and reproduced as data, sound, or visual information. The invention also involves methods of modifying the symbology in the curved symbology portions of the encodement to compensate for the distortion that is occasioned by imaging the curved symbology portions in the planar symbology image.
In certain preferred embodiments of the invention, the symbology is invisible or substantially invisible to the human eye when viewed under normal viewing conditions and is recorded over a visible image in the image field. Additionally, the objects on which the image fields are printed or recorded are preferably curved in one direction or in two directions, and may comprise cylindrical objects, spherical objects and print media that is curved at least in part when viewed. A great deal of data can be encoded into such invisible encodements extending over the full, visible image without obscuring or degrading it.
It is an advantageous effect of at least some of the embodiments of the invention that variable data encodement can be undertaken with respect to image fields on curved surfaces and that these encodements can be captured and accurately decoded using a simple, hand held, planar imager. The curved surfaces include magazine or book pages that are curved at least in part when a page is exposed for view, due to the binding of the book or magazine. Similarly, the variable data encodement can be undertaken for image fields that are even more or less curved, e.g., cylindrical surfaces or spherical surfaces.